Endress+Hauser Prothermo NMT81 Technical specifications

Products Solutions Services
Brief Operating Instructions
Prothermo NMT81
Tank Gauging
These Instructions are Brief Operating Instructions; they are
not a substitute for the Operating Instructions pertaining to
the device.
Detailed information about the device can be found in the
Operating Instructions and the other documentation:
Available for all device versions via:
• Internet: www.endress.com/deviceviewer
• Smart phone/tablet: Endress+Hauser Operations App
KA01533G/00/EN/01.21
71529914
2021-10-11

Prothermo NMT81
2 Endress+Hauser
Order code:
Ext. ord. cd.:
Ser. no.:
www.endress.com/deviceviewer Endress+Hauser
Operations App
XXXXXXXXXXXX
XXXXX-XXXXXX
XXX.XXXX.XX
Serial number
1.
3.
2.
A0023555

Prothermo NMT81 Table of contents
Endress+Hauser 3
Table of contents
1 About this document .............................................................. 4
1.1 Document conventions .................................................................. 4
1.2 Documentation ........................................................................ 6
1.3 Registered trademarks .................................................................. 7
2 Basic safety instructions .......................................................... 7
2.1 Requirements for the personnel ............................................................ 7
2.2 Intended use .......................................................................... 7
2.3 Workplace safety ...................................................................... 7
2.4 Operational safety ......................................................................8
2.5 Product safety ......................................................................... 8
3 Product description ............................................................... 8
3.1 Product design ........................................................................ 8
4 Incoming acceptance and product identification ................................. 10
4.1 Incoming acceptance .................................................................. 10
4.2 Product identification .................................................................. 10
4.3 Manufacturer contact address ............................................................ 11
4.4 Storage and transport .................................................................. 12
5 Installation ...................................................................... 13
5.1 Converter ........................................................................... 13
5.2 Option 1: Converter with universal coupling .................................................. 13
5.3 Option 2: Converter with M20 mounting thread ............................................... 15
5.4 Converter + average temperature probe version ............................................... 16
5.5 Converter + average temperature probe + water bottom probe .................................... 18
5.6 Flanges ............................................................................ 20
5.7 Element No. 1 position ................................................................. 21
5.8 WB probe design ..................................................................... 23
5.9 Pre-installation of NMT81 .............................................................. 26
5.10 Installation procedure .................................................................. 27
5.11 Mounting NMT81 on a cone roof tank ...................................................... 32
5.12 Mounting NMT81 on a floating roof tank ................................................... 39
5.13 Mounting NMT81 on a pressurized tank .................................................... 45
6 Electrical connection ............................................................ 47
6.1 NMT81 (Ex ia) intrinsically safe connection .................................................. 47
6.2 NMT81 transmitter and element connection ................................................. 49
6.3 NMS8x/NMR8x/NRF81 (Ex d [ia]) intrinsically safe connection ................................... 49
6.4 NMS5 (Ex d [ia]) intrinsically safe connection ................................................ 51
6.5 NRF590 terminals .................................................................... 52
7 Commissioning .................................................................. 53
7.1 Terms related to temperature measurement ................................................. 53
7.2 Initial setting ........................................................................ 54
7.3 Initial screen ......................................................................... 54
7.4 Guidance ........................................................................... 57

About this document Prothermo NMT81
4 Endress+Hauser
1 About this document
1.1 Document conventions
1.1.1 Safety symbols
DANGER
This symbol alerts you to a dangerous situation. Failure to avoid this situation will result in
serious or fatal injury.
WARNING
This symbol alerts you to a dangerous situation. Failure to avoid this situation can result in
serious or fatal injury.
CAUTION
This symbol alerts you to a dangerous situation. Failure to avoid this situation can result in
minor or medium injury.
NOTICE
This symbol contains information on procedures and other facts which do not result in
personal injury.
1.1.2 Electrical symbols
Alternating current
Direct current and alternating current
Direct current
Ground connection
A grounded terminal which, as far as the operator is concerned, is grounded via a grounding
system.
Protective earth (PE)
Ground terminals that must be connected to ground prior to establishing any other
connections.
The ground terminals are located on the interior and exterior of the device:
• Interior ground terminal: protective earth is connected to the mains supply.
• Exterior ground terminal: device is connected to the plant grounding system.
1.1.3 Tool symbols
Phillips head screwdriver
Flat blade screwdriver

Prothermo NMT81 About this document
Endress+Hauser 5
Torx screwdriver
Allen key
Open-ended wrench
1.1.4 Symbols for certain types of information and graphics
Permitted
Procedures, processes or actions that are permitted
Preferred
Procedures, processes or actions that are preferred
Forbidden
Procedures, processes or actions that are forbidden
Tip
Indicates additional information
Reference to documentation
Reference to graphic
Notice or individual step to be observed
1.
,
2.
,
3.
Series of steps
Result of a step
Operation via operating tool
Write-protected parameter
1, 2, 3, ...
Item numbers
A, B, C, ...
Views
Safety instructions
Observe the safety instructions contained in the associated Operating Instructions

About this document Prothermo NMT81
6 Endress+Hauser
1.2 Documentation
The following documentation types are available in the Downloads area of the Endress
+Hauser website (www.endress.com/downloads):
For an overview of the scope of the associated Technical Documentation, refer to the
following:
•W@M Device Viewer (www.endress.com/deviceviewer): Enter the serial number from
nameplate
•Endress+Hauser Operations App: Enter the serial number from the nameplate or scan
the 2D matrix code (QR code) on the nameplate
1.2.1 Technical Information (TI)
Planning aid
The document contains all the technical data on the device and provides an overview of the
accessories and other products that can be ordered for the device.
1.2.2 Brief Operating Instructions (KA)
Guide that takes you quickly to the 1st measured value
The Brief Operating Instructions contain all the essential information from incoming
acceptance to initial commissioning.
1.2.3 Operating Instructions (BA)
The Operating Instructions contain all the information that is required in various phases of
the life cycle of the device: from product identification, incoming acceptance and storage, to
mounting, connection, operation and commissioning through to troubleshooting,
maintenance and disposal.
1.2.4 Description of Device Parameters (GP)
The Description of Device Parameters provides a detailed explanation of each individual
parameter in the operating menu(except the Expert menu). The description is aimed at those
who work with the device over the entire life cycle and perform specific configurations.
1.2.5 Safety Instructions (XA)
Depending on the approval, the following Safety Instructions (XA) are supplied with the
device. They are an integral part of the Operating Instructions.
The nameplate indicates the Safety Instructions (XA) that are relevant to the device.
1.2.6 Installation instructions (EA)
Installation Instruction are used to replace a faulty unit with a functioning unit of the same
type.

Prothermo NMT81 Basic safety instructions
Endress+Hauser 7
1.3 Registered trademarks
FieldCare®
Registered trademark of the Endress+Hauser Process Solutions AG, Reinach, Switzerland
2 Basic safety instructions
2.1 Requirements for the personnel
The personnel must fulfill the following requirements for its tasks:
‣Trained, qualified specialists must have a relevant qualification for this specific function
and task.
‣Are authorized by the plant owner/operator.
‣Are familiar with federal/national regulations.
‣Before starting work, read and understand the instructions in the manual and
supplementary documentation as well as the certificates (depending on the application).
‣Follow instructions and comply with basic conditions.
2.2 Intended use
Application and measured materials
Measuring devices for use in hazardous areas, in hygienic applications or in applications
where there is an increased risk due to process pressure, are labeled accordingly on the
nameplate.
To ensure that the measuring device remains in proper condition for the operation time:
‣Only use the measuring device in full compliance with the data on the nameplate and the
general conditions listed in the Operating Instructions and supplementary documentation.
‣Check the nameplate to verify if the device ordered can be put to its intended use in the
approval-related area (e.g. explosion protection, pressure vessel safety).
‣If the measuring device is not operated at atmospheric temperature, compliance with the
relevant basic conditions specified in the associated device documentation is absolutely
essential.
‣Protect the measuring device permanently against corrosion from environmental
influences.
‣Observe the limit values in the "Technical Information".
The manufacturer is not liable for damage caused by improper or non-designated use.
2.3 Workplace safety
For work on and with the device:
‣Wear the required personal protective equipment according to federal/national
regulations.

Product description Prothermo NMT81
8 Endress+Hauser
2.4 Operational safety
Risk of injury!
‣Operate the device only if it is in proper technical condition, free from errors and faults.
‣The operator is responsible for interference-free operation of the device.
Hazardous area
To eliminate danger to persons or the facility when the device is used in the hazardous area
(e.g. explosion protection):
‣Check the nameplate to verify if the device ordered can be put to its intended use in the
hazardous area.
‣Observe the specifications in the separate supplementary documentation that is an integral
part of these instructions.
2.5 Product safety
This measuring device is designed in accordance with good engineering practice to meet state-
of-the-art safety requirements, has been tested, and left the factory in a condition in which it
is safe to operate. It meets general safety standards and legal requirements.
NOTICE
Loss of degree of protection by opening of the device in humid environments
‣If the device is opened in a humid environment, the degree of protection indicated on the
nameplate is no longer valid. This may also impair the safe operation of the device.
2.5.1 CE mark
The measuring system meets the legal requirements of the applicable EU Directives. These are
listed in the corresponding EU Declaration of Conformity along with the standards applied.
Endress+Hauser confirms successful testing of the device by affixing to it the CE mark.
3 Product description
3.1 Product design
NMT81 converter + average temperature probe version can be equipped with class A IEC
60751/DIN EN 60751 or class 1/10B Pt100 4-wire RTD sensor elements in its protective
probe for up to 24 elements. It is able to accurately measure the temperature of each element
by measuring its temperature dependent resistance. NMT81 converter + temperature probe
version conforms to intrinsic safety standards, and because NMT81 consumes very little
power, it guarantees superior safety as an electrical device that is installed in tanks in
hazardous locations, and ecological/environmentally friendly as well.

Prothermo NMT81 Product description
Endress+Hauser 9
12
4
5
1
3
4
5
6
6
1.
A1.
B
A0042800
 1 Design of Prothermo NMT81
A NMT81 with water bottom (WB)
B NMT81 without water bottom (WB)
1 Converter
2 Welded flange
3 Adjustable flange
4 Flexible sensor probe
5 Water bottom (WB) sensor probe
6 Flexible sensor probe without WB

Incoming acceptance and product identification Prothermo NMT81
10 Endress+Hauser
4 Incoming acceptance and product identification
4.1 Incoming acceptance
Upon receipt of the goods check the following:
• Are the order codes on the delivery note and the product sticker identical?
• Are the goods undamaged?
• Do the nameplate data match the ordering information on the delivery note?
• If required (see nameplate): Are the Safety Instructions (XA) enclosed?
If one of these conditions is not satisfied, contact your Endress+Hauser Sales Center.
4.2 Product identification
The following options are available for identification of the measuring device:
• Nameplate specifications
• Extended order code with breakdown of the device features on the delivery note
•W@M Device Viewer (www.endress.com/deviceviewer): Enter the serial number from the
nameplate
•Endress+Hauser Operations App: Enter the serial number from the nameplate or scan the
matrix code on the nameplate
For an overview of the scope of the associated Technical Documentation, refer to the
following:
•W@M Device Viewer (www.endress.com/deviceviewer): Enter the serial number from
the nameplate
•Endress+Hauser Operations App: Enter the serial number from the nameplate or scan
the matrix code on the nameplate

Prothermo NMT81 Incoming acceptance and product identification
Endress+Hauser 11
4.2.1 Nameplate
56
Prothermo
Date:
Order code: Ser. no.:
Ext. ord. cd.:
# Elements:
Length =
Mat.:
WB length =:
FW:
Dev.Rev.:
HW:
certificate:
14...30 V DC 2-wire HART
MWP:
Ta: -40...+60°C Tp:
1
23
4
5
6
8910
11
12 13 14
15 16
17
18 19
20 21
23 24
25
22
7
T ≥ Ta +20K
A0042783
 2 Nameplate of Prothermo NMT81
1 Manufacturer address
2 Order code
3 Serial number
4 Extended order code
5 Intrinsically safe parameters
6 Process temperature
7 Maximum working pressure
8 Length of temperature sensor probe
9 Number of elements
10 Length of Water Bottom
11 Material in contact with process
12 Firmware version
13 Hardware revision
14 Cable entry standard
15 Device revision
16 Ingress protection
17 Additional information of the device version
18 PTB certification number (for PTB approval type)
19 Manufacturing date
20 Certificate symbol
21 Data concerning Ex approvals
22 Associated Safety Instruction (XA)
23 Associated Safety Instruction (XA) for Local language
24 Manufacturer info. for local language
25 Device data for local language
4.3 Manufacturer contact address
Endress+Hauser Yamanashi Co., Ltd.
406-0846
862-1 Mitsukunugi, Sakaigawa-cho, Fuefuki-shi, Yamanashi

Incoming acceptance and product identification Prothermo NMT81
12 Endress+Hauser
4.4 Storage and transport
4.4.1 Storage conditions
• Storage temperature: –40 to +85 °C (–40 to +194 °F)
• Store the device in its original packaging.
4.4.2 Transporting to the measuring point
LCAUTION
Risk of injury
‣Follow the safety instructions and transport conditions for devices weighing more than
18 kg (39.69 lb).

Prothermo NMT81 Installation
Endress+Hauser 13
5 Installation
5.1 Converter
182.3 (7.18)
96.9
(3.81)
147 (5.79)
Ø100.9
(3.97)
A0045260
 3 Standard converter
5.2 Option 1: Converter with universal coupling
1
2
339.3 (13.36)
192.8 (7.59)
52
(2.05)
A0047059
 4 Option 1: converter (Standard G3/4 (NPT 3/4) universal coupling connection)
1 G 1/2 dummy plug
2 G 3/4 thread

Installation Prothermo NMT81
14 Endress+Hauser
5.2.1 Option 1: Measurement functions
Because the software in the converter is equipped with a function that converts elements with
different characteristics, it is possible to use other brand's temperature probes.
The NMT81 converter only version supports the following element types:
Elements Standard Temperature coefficient
Pt100 IEC60751 α=0.00385
Pt100 GOST α=0.00391
Cu100 GOST α=0.00428
Ni100 GOST α=0.00617
• If elements other than the items above are required, contact your Endress+Hauser
Sales Center.
• NMT81 is four-wire only with MSTs (Multi-spot thermometers), but it is not
compatible with a thermocouple temperature device.
• The physical connection between a probe and NMT81 is completed by a zinc-plated
carbon steel G 3/4" (NPT 3/4") universal threaded coupling. If a different thread size is
required, Endress+Hauser can provide a solution by adapting a variety of coupling sizes
and materials based on existing temperature probe specifications. Contact your
Endress+Hauser Sales Center.
• Power supply and data transmission lines are both provided from the host gauge of
NMS5, NMS8x, NMR8x, NRF81 or NRF590 through a two-wire local HART loop
connection. NMT81 can be configured and operated using FieldCare, which has a user-
friendly interface.

Prothermo NMT81 Installation
Endress+Hauser 15
5.3 Option 2: Converter with M20 mounting thread
This option model is designed specifically to connect with a Whessoe Varec 1700 series
average temperature probe. WB data is not available because the 1700 series does not have
WB.
182.3 (7.18)
M20
32 (1.26)
37
(1.46) 1
2
A0042766
 5 Option 2: converter (Varec 1700, M20 threaded connection). Unit of measurement mm (in)
1 Existing 1700 series RT probe terminal box on-site
2 Lock nut
UK model M20 threaded type and Varec 1700 terminal housing connection procedure
1. Use sealing tape to protect the threaded connection opening, and insert the cable
bundle (RTD signal entry cable) into the female threaded connection opening on the
terminal box.
2. Screw on the NMT81 converter by rotating it at least 10 times clockwise, and secure it
with a lock nut.
 A loose connection between NMT81 and Varec1700 terminal housings will lead to
malfunction due to ingress of flood and other factors.
This completes the procedure.
5.3.1 Option 2: Measurement functions
Option 2 has the same functions as option 1; however, option 2 is designed so that a special
M20 threaded connection opening fits directly in the existing terminal housing of a Varec
1700. The wiring of RTD signals from the probe to NMT81 is done in the terminal box of the
Varec 1700 and not on the NMT81 side. For this reason, there is no additional housing
provided to NMT81 as in option 1.

Installation Prothermo NMT81
16 Endress+Hauser
5.4 Converter + average temperature probe version
Ø27.2
(1.07)
d
c: 19.5 (0.77)
Ø27.2
(1.07)
a
182.3
(7.18)
b
180
(7.09)
b
180
(7.09)
Ø100.9
(3.97)
d
1
2
3
Ø100.9
(3.97)
a
182.3
(7.18)
c: 19.5 (0.77)
Ø27.2
(1.07)
d
1
2
3
AB
A0042769
 6 Converter + average temperature probe. Unit of measurement mm (in)
A Adjustable flange
B Welded flange
a Converter height
b Adjustable installation height
c Based on flange standards
d Temperature probe length (see below)
1 316L
2 316L
3 316L

Prothermo NMT81 Installation
Endress+Hauser 17
The following tolerances are applied regardless of an optional WB probe. However, the
position of the flange cannot be adjusted in a welded flange type.
Probe length Tolerance of probe and element positions
1 000 to 25 000 mm (39.37 to 984.25 in) ± 50 mm (1.97 in)
25 001 to 40 000 mm (984.29 to 1 574.80 in) ± 50 mm (1.97 in)
40 001 to 60 000 mm (1 574.84 to 2 362.21 in) ± 100 mm (3.94 in)
60 001 to 100 000 mm (2 362.24 to 3 937.01 in) ± 300 mm (11.81 in)

Installation Prothermo NMT81
18 Endress+Hauser
5.5 Converter + average temperature probe + water bottom probe
3
c: 19.5 (0.77)
Ø27.2
(1.07)
a
182.3
(7.18)
b
180
(7.09)
b
180
(7.09)
Ø100.9
(3.97)
d
Ø42.7
(1.68)
7
7
Ø42
(1.65)
10 (0.39)
d
e
530 /1030/2030
(20.87/40.55/79.92)
f
Ø100.9
(3.97)
a
182.3
(7.18)
c: 19.5 (0.77)
d
34
5
6
6
1
2
1
2
5
AB
A0042767
 7 Converter + temperature probe + WB probe. Unit of measurement mm (in)
A Adjustable flange
B Welded flange
a Converter height
b Adjustable installation height
c Based on flange standards
d Probe length (from flange bottom to the tip of WB probe) (see below)
e Capacitance WB probe

Prothermo NMT81 Installation
Endress+Hauser 19
f Anchor weight hook (316L)
1 316L
2 316L
3 PFA protection tube (thickness 1 mm (0.04 in))
4 Sensor pipe (304)
5 Pt100 element
6 Base plate/side rod (316L)
7 Element
The following tolerances are applied regardless of an optional WB probe. The position of the
flange cannot be adjusted in a welding flange type.
Probe length Tolerance of probe and element positions
1 000 to 25 000 mm (39.37 to 984.25 in) ± 50 mm (1.97 in)
25 001 to 40 000 mm (984.29 to 1 574.80 in) ± 50 mm (1.97 in)
40 001 to 60 000 mm (1 574.84 to 2 362.21 in) ± 100 mm (3.94 in)
60 001 to 100 000 mm (2 362.24 to 3 937.01 in) ± 300 mm (11.81 in)

Installation Prothermo NMT81
20 Endress+Hauser
5.6 Flanges
Welded flanges are more watertight because the joint is completely welded together.
However, the position of welded flanges cannot be adjusted.
Ø100.9
(3.97)
182.3 (7.18)
1
96.9 (3.81)
147 (5.79)
A0042770
 8 Welded flange. Unit of measurement mm (in)
1 Flange (JIS, ASME, JPI, DIN)